maplemale avatar image
maplemale asked

Equalization time WAY too short + BMV-712 charge drift (defective BVM?)

MPPT 150/135
2*200 Watt Mono Panels (on a boat)
Smart BVM-712
4*6v Wet Cell 230AH (SLGI115)

14.7 Absorption
13.95 Float
15.15 Equalization

Charged Voltage: 14.4
Tail Current: 4%

Charged detection time: 15m
Peukert Exponent:1.25

Latest firmware on both as of last week.

Mainly, the equalization cycle lasts only about an hour and doesn't seem to care what the voltage is (it was at 14.4v when it stopped and went to "float"). I was cycling it manually after it went into absorption mode. Second time, same result (though at 14.6v this time). Seems broken / bad design or I have some other issue. How can I make it stay on until the 15.15v that I have it set to is reached?

Secondly, the BVM-712 percentage is rather useless if I can't turn the "Charged detection time" setting completely off. It causes massive drift even at the max setting (15 minutes). I've had it jump from 85% to 100% late in the afternoon when it's getting a very low trickle charge. Is there any way to turn this feature completely off? It seems completely useless for a solar setup where the charging current is commonly going to be < than the tail current for extended periods of time in the morning, evening and during a storm. Or am I just misunderstanding what the definition of this setting is? Please tell me if I'm wrong, but it seems like it would regularly cause drift in solar setups even at the max minutes

MPPT ControllersBMV Battery Monitor
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1 Answer
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi Maplemale! Sorry for the slow response.

For the BMV; try increasing the charge voltage setting. Also there is a chapter in the manual about this; (I think?) did you check there?

And for the equalize: was that resolved in the mean time? And are its workings as per explanation here? -> Battery settings

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maplemale avatar image maplemale commented ·

Thanks... please disregard the question regarding the BMV. I understand how this works now and use the information appropriately.

Regarding Equalize, the question remains regardless of whether it's working as intended or not (which it is). I question the design here. Maybe I'm missing something, but I find myself bypassing your controller to do this properly as do others I've spoken with.

Why the time limits as described in the documentation you provided specifically for lead acid setups? I shouldn't be forced to hit the manual equalize button 4-5 times to complete (would by typical in most lead acid setups). I understand the current detection functionality shutting down an equalize cycle - but the relationship drawn to the absorption time and the 1 hour limit on manual equalize doesn't make sense to me. Equalization shouldn't have much to do with absorption IMHOP and a proper equalize is almost always going to take multiple hours regardless.

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